This invention relates to an apparatus for the assembly of radial tire components, and more particularly, to a ply server assembly having means for drawing a preselected length of ply material from a supply roll and applying it onto a carcass building drum.
Previous methods for building the first stage cylindrical carcass have required manually measuring and cutting a length of ply material drawn from a large supply roll and applying it onto a carcass building drum. Such an operation is relatively time consuming and expensive to perform. It also requires the operator/builder to physically handle the various uncured lengths (or sheets) of ply material.
When applying the two-stage method of assembling a modern radial tire, it is common to use a first stage carcass assembly machine and a second stage machine on which the carcass from the first stage is chucked by its beads and then transformed from a cylinder into a toroidal shape, at which time the belt-tread stock package is added to the carcass, and the assembly is then consolidated by stitching the two tacky subassemblies together.
The basic elements of a modern radial ply pneumatic tire consist of an inner liner, one or more plies, sidewalls, beads, fillers and other bead reinforcements, all of which, when properly assembled, form an assembly called a first stage carcass, as well as a belt-tread stock assembly comprising one or more belts incorporating steel cord or other suitable cord materials and a length of tread stock combined to form a belt-tread stock package or second stage assembly. The first stage carcass and the belt-tread stock package are then combined into a green tire, which is subsequently molded and cured in a vulcanizer.
One form of apparatus for combining the two assemblies is described in U.S. Pat. No. 4,402,782 issued Sep. 6, 1983, to the assignee of this application. The two major assemblies are produced on two distinct and separate types of apparatus which are then combined into a so-called green tire.
The carcass is initially cylindrical and consists of one or more body plies of rubber coated cord, a pair of axially spaced parallel bead rings, layers of the ply material which encompass the bead rings, and side wall stock material. These tire elements are typically assembled in a manually operated apparatus, and consolidated on a cylindrical carcass building drum into the shape of a cylinder. Then the cylindrical carcass is loaded, in most cases manually, onto a tire building or assembly drum (FIGS. 18 and 19 of said U.S. Pat. No. 4,402,782) and re-shaped into a toroidal carcass.
The handling and storage of carcass components adds many uncontrollable and undesirable process variables to the product, such as exposure to touching by human hands and associated exposure to dirt, grease, perspiration, remnants of soap or detergents or skin creams. In addition, there is an undetermined exposure to airborne particles which deposit on the outer surface of the carcasses. The unknown duration of that exposure, anywhere from one hour to three or four days (on long weekends), results in undesirable distortions and carcass deformations.